As the world eagerly anticipates the arrival of flying taxis in cities, concerns regarding the potential noise they would generate are being raised by urban residents. However, Tennessee-based startup Whisper Aero has recently revealed its electric propulsion technology, offering a solution for noiseless aerial transportation in the future.

Drones and vertical take-off and landing vehicles (VTOLs) have the potential to alleviate road congestion and revolutionize urban travel. Nevertheless, the noise emissions associated with these systems have been a source of frustration. After years of efforts to relocate airports away from cities, we find ourselves on the cusp of a future where noise pollution from above may become a concern, potentially hindering the prospects of air taxis within city limits.

In 2021, Mark Moore and Ian Villa, former colleagues at Uber Elevate, co-founded Whisper Aero with the aim of spearheading a silent revolution in electric propulsion and transforming noiseless flight into a reality. After eight months of development, the startup successfully flew a drone powered by its noiseless technology and has now unveiled the groundbreaking technology behind it.

At the heart of Whisper Aero’s ultra-quiet electric jet lies a propulsion disc—an assembly of numerous blades interconnected by a shrouding ring. The disc’s small diameter ensures that blade tip speeds remain low while allowing revolutions to increase for flight. By incorporating a large number of blades, the company pushes the blade passage frequency beyond 16,000 Hertz, rendering the noise produced inaudible to human ears and even to dogs. Although the engines do generate sound, it falls outside the range of detectability. Moreover, the multitude of blades enables the propulsion disc to rotate at a significantly slower speed than traditional aircraft propellers. The shrouding ring further minimizes the potential for noise generation by eliminating gaps between the blade tips and the duct housing.

During testing, a six-inch propulsion disc produced an audible sound from a distance of 200 feet (61 meters). In comparison, ducted fans and propellers with similar thrust generated noise levels of up to 52 dBA and 59 dBA, respectively, while Whisper’s technology measured only 34 dBA.

Given the small size of the propulsion disc, Whisper Aero needs to incorporate multiple units to generate the necessary lift for an aircraft. As a result, the aircraft may appear unconventional in its design. Nevertheless, this does not undermine the company’s confidence in its capabilities. The aircraft, designed for conventional take-off and landing, can accommodate nine passengers and a pilot, reaching speeds of 288 miles (463 km) per hour. With a full charge, the aircraft has a range of 200 miles (322 km), but Whisper Aero is also exploring the potential to extend this to 500 miles (800 km) using a hybrid system.

For now, Whisper Aero remains focused on refining its propulsion design and increasing the fan’s diameter. While the company is open to designing complete aircraft, it also aims to provide its silent propulsion technology to other manufacturers, contributing to a broader adoption of noiseless flying taxis beyond its own production capacity.

By Impact Lab